Bisoxalic acid diamides as stabilizers

ABSTRACT

BISOXALIC ACID DIAMINES HAVING THE STRUCTURE   ((4-HO,3,5-DI((CH3)3-C-)PHENYL)-NH-CO-CO-NH)2-R   WHERE R IS AN ALKYLENE GROUP HAVING 5 TO 18 CARBON ATOMS ARE STABILIZERS OF ORGANIC MATERIALS SUCH AS POLYOLEFINS. THESE COMPOUNDS ARE PREPARED BY REACTING AN OXALIC ACID MONOAMIDE OR THE CHLORIDE OR AN ESTER THEREOF WITH AN ALKYLENE DIAMINE.

United States Patent Olfice 3,734,884

Patented May 22, 1973 wherein m represents a whole number from 6 to 8. 3,734,884 The above characterised compounds can be produced BISOXALIC ACID DIAMIDES As STABILIZERS by processes analogous to processes known per se. Max Dunnenberger, Frenkendorf, and Hans Rudolf Bl- Basically a compound of the formula land, Gelterkinden, both of Basel-Land, Switzerland, assignors to Ciba-Geigy AG, Basel, Switzerland (4) (013M110 No Drawing. Original application Apr. 12, 1971, Ser. No.

133,377. Divided and this application June 15, 1972, 110- X Ser- No. 263,339 U S C] %1t c 1 c07c 103/14,- cosr 45/60 Cl NC 3 aims 10 is thereby reacted with a compound of the formula ABSTRACT OF THE DISCLOSURE (5) Bisoxalic acid diamines having the structure X and represent either 2 C(CHa)a o 1 -NHCO COY I ll wherein Y stands for C1, -OH or an alkoxy group HO O NH C NHR having 1 to 12 carbon atoms. R has the above given CH J meaning. X and X must be different in the two reactants. 2 This means that one mole of a compound of the formula where R 1s an alkylene group havmg 5 to 18 carbon atoms 20 (6) O O O are stabilizers of organic materials such as polyolefins. g H g g These compounds are prepared by reacting an oxalic acid monoamide or the chloride or an ester thereof with an wherein Y and R have the given meaning is reacted with alkylene diamine. 2 moles of 3,S-di-tert.butyl-4-hydroxy-aniline; or 1 mole of a diamine of the formula This application is a division of our prior application Ser. No. 133,377, filed Apr. 12, 1971. (7) 2 DETAILED DESCRIPTION wherein R has the given meaning is reacted with 2 moles It is already known that a large number of bisoxalic of a compound of the formula acid diamides can be used as ultraviolet absorbers. (8) (CHQSC O 0 It has now been found by a further study of this field 5 that a selected group of new bisoxalic acid diamides H0 NH"C possess, as anti-oxidants, outstanding properties which are lacking in compounds of very similar constitution. (CHQ These new bisoxalic acid diamides correspond to the wherein Y has the given meaning. formula In Formula 6 the symbol Y hereby represents prefer- (C 3)aC C(C a)s wherein R represents an alkylene radical having 5 to 18 ably chlorine, whilst in Formula 8 it preferably stands carbon atoms. for an alkoxy group having 1 to 12 carbon atoms.

The alkylene radical R in Formula 1 can be branched The condensation according to the above defined reacor, preferably, unbranched. tion is performed, depending on the reactivity of the Of particular practical interest, especially as anti-oxifunctional group to be reacted, at temperatures between dants for poly-a-olefins, are bisoxalic acid diamides of the 0 and 250 C. in a solvent inert to the reactants, or in the formula melt, optionally in the presence of a condensation cat- 0 CH alaC I I :03 no- -N11 c :-NH-(em NH-d-e-HN OH (CHslz C(CHa)8 wherein n represents a whole number from 6 to 10. alyst. Preferred condensation catalysts are tertiary amines Preferred compounds within the scope of Formula 2 such as triethanolamine and pyridine, also acids such as correspond to the formula boric acid and p-toluenesulphonic acid. The amount of CH 0 C c a)a I? H I Ha)a HO NH-CC-NH{OHz}NHC1-HN 0H 3 catalyst to be used is, in general, to percent by weight, relative to the total weight of the reactants. Preferably, the reaction is performed in a solvent at a temperature of 30 to 80 C. Suitable solvents are, for example,

4 point: 139 to 140 C.), is refluxed, with stirring, in 60 cubic centimetres of ethanol with 1.2 g. of 1,6-diaminohexane for 3 hours. The reaction mixture is subsequently cooled to 10 0, whereby the product of the formula aromatic hydrocarbons, or aromatic halogenated hydrocarbons such as benzene, toluene, p-cymol, chlorobenzene, diand trichlorobenzene, alcohols or ethers, such as methanol, ethanol, ethylene glycol, diethylene glycol, triethylene glycol, glycerin, ethylene glycol monomethyl ether, diethylene glycol diethyl ether, and dioxane, or also methylene chloride.

The compound of Formula 8 wherein Y represents alkoxy is produced, for example, by reaction of l-amino- 3,5-di-tert.butyl-4-hydroxybenzene with oxalic acid monoalkylester-chloride in benzene with pyridine as HClacceptor.

The described new compounds constitute valuable antioxidants, ie they are suitable for the stabilization of organic materials to oxidative decomposition, by which is meant, in particular, thermally accelerated oxidations. Materials which can be protected are: homoand copolymerisates made from ethylenically unsaturated compounds such as vinyl chloride, vinylidene chloride, styrene, butadiene, isoprene, ethylene, propylene, acrylicand methacrylic acid derivatives, e.g. acrylic acid alkyl ester, acrylic acid amides, and acrylonitrile; polyamides, e.g. made from e-caprolactam, or from adipic acid and a diamine; polyesters such as terephthalic acid glycol polyesters; natural and synthetic rubbers; lubricating oils; benzines; vegetable and animal oils and fats; waxes; cellulose and cellulose derivatives such as cellulose ester.

To be specially emphasised is the excellent anti-oxidant elfect of the above defined compounds in the case of polymerisate synthetic materials, particularly poly-a-olefins such as polypropylene.

Sufficient for a good anti-oxidant effect is, in general, an amount of 0.01 to 5%, preferably 0.1 to 2% of the compounds according to the invention, relative to the substrate to be protected. The anti-oxidants can be worked on their own into the materials to be protected, or together with other additives such as softeners, pigments, protective agents against light-rays (UV-absorbers), secondary anti-oxidants, optical brighteners, with or without the aid of solvents.

The good stabilising eflFect of the new compounds is shown, e.g. under accelerated ageing conditions at temperatures above 100 C. A polypropylene subjected to these conditions which contains an anti-oxidant does not show signs of a discolouration, or of the material becoming tender, until after a very much longer time than the time required for this to occur in the case of a polypropylene containing no stabiliser.

Where not otherwise stated in the following examples, the term parts denotes parts by Weight, and the term percent denotes percent by weight. The melting points of the new compounds are not corrected.

EXAMPLE 1 An amount of 6.4 g. of the compound of the formula (9) (CH3)3C precipitates in the form of colourless crystals. Yield: approximately 7 g.

After recrystallisation three times from ethanol, the analytical product melts at 230 to 231 C.

The following compounds of Formula 1 are produced in an analogous manner:

A mixture of parts of stabiliser-free polypropylene (Profax 6501, Hercules Powder) and 0.2 part of a compound according to the below given table is processed on a calendering machine at 170 C. into a soft sheet, and this subsequently pressed at 230 C., and under a pressure of 40 kg./cm. to form a plate of 1 mm. thickness. The thus obtained plates are subjected at C. (air, normal pressure) to an accelerated oxygen ageing treatment. The time passing before the appearance of the first cracks detectable with the eye is a measure of the antioxidative effect of the added compound.

TABLE 1 Time in hours until cracks Added compound: form at 140 C.

Without addition 5 Commercial anti-oxidants:

2,6-di-tert.butyl 4 methylphenol 25 Methy1ene-bis-( 3 methyl 4 hydroxy-S-tert.

butylbenzene) 28 Thio-bis-(2methyl 4 hydroxy 5 -tert.butylbenzene) 100 TABLE II Compounds according to the invention Compound of Time in hours until cracks the formula: form at 140 C. (10) 2250 (11) 2250 (12) 2000 (14) 1830 What is claimed is: 2. A composition of matter consisting essentially of a 1. A composition of matter consisting essentially of poly-a-olefin and from 0.01 to 5% by weight, based on said polyolefin, of a bisoxalic acid diamide of the formula a poly-a-olefin and from 0.01 to 5% by weight, based on said polyolefin, of a bisoxalic acid diamide of the formula Wherem a Whole number from 6 to if 0 1? HO NH-ii-G-NH-R-NH-iL-G-NH- OH 3): s): wherein R is an alkylene radical having 5 to 18 carbon 3. A composition of claim 2 wherein the polyolefin is atoms. polypropylene.

References Cited UNITED STATES PATENTS 3,034,879 5/1962 Spacht 26045.9 NC 3,211,562 10/1965 Biland et al 26045.9 NC 3,357,944 12/1967 Dexter 26045.9 NC 3,542,573 11/1970 Biland et al 26045.9 NC 3,639,249 2/1972 Luethi et a1 26045.9 NC 3,677,965 7/ 1972 Dexter et a1 26045.9 NC 3,683,020 8/ 1972 Luethi et al 26045.9 NC

DONALD E. CZAJ A, Primary Examiner R. W. GRIFFIN, Assistant Examiner US. Cl. X.R. 

